Articles containing coatings of amic acid salts

ABSTRACT

An article includes a flexible or rigid substrate and dry layer comprising an aromatic, non-polymeric amic acid salt that can be thermally converted to a corresponding arylene diimide. Upon conversion of the aromatic, non-polymeric amic acid salt, the dry layer has semiconductive properties and can be used in various devices including thin-film transistor devices.

FIELD OF THE INVENTION

This invention relates to articles having a substrate and a coating of aunique non-polymeric amic acid salt. The coatings in these articles canbe converted into semiconductive layers to provide various usefulsemiconductive devices.

BACKGROUND OF THE INVENTION

Considerable efforts have been made to discover new organicsemiconductor materials that can be used in FET's to provide switchingor logic elements in electronic components, many of which requiresignificant mobilities well above 0.01 cm²/V.sec, and current on/offratios (hereinafter referred to as “on/off ratios”) greater than 1000.Organic FET's (“OFET's”) having such properties can be used forelectronic applications such as pixel drivers for displays andidentification tags. However, most of the compounds exhibiting thesedesirable properties are “p-type” or “p-channel,” meaning that negativegate voltages, relative to the source voltage, are applied to inducepositive charges (holes) in the channel region of the device.

As an alternative to p-type organic semiconductor materials, n-typeorganic semiconductor materials can be used in FET's where theterminology “n-type” or “n-channel” indicates that positive gatevoltages, relative to the source voltage, are applied to induce negativecharges in the channel region of the device.

Moreover, one important type of FET circuit, known as a complementarycircuit, requires an n-type semiconductor material in addition to ap-type semiconductor material. Simple components such as inverters havebeen realized using complementary circuit architecture. Advantages ofcomplementary circuits, relative to ordinary FET circuits, include lowerpower dissipation, longer lifetime, and better tolerance of noise. Insuch complementary circuits, it is often desirable to have the mobilityand the on/off ratio of an n-channel device similar in magnitude to themobility and the on/off ratio of a p-channel device. Hybridcomplementary circuits using an organic p-type semiconductor and aninorganic n-type semiconductor are known, but for ease of fabrication,an organic n-channel semiconductor material would be desired in suchcircuits.

Only a limited number of organic materials have been developed for useas a semiconductor n-channel in OFET's. One such material,buckminsterfullerene C₆₀, exhibits a mobility of 0.08 cm²/V.sec but itis considered unstable in air (Haddon et al. Appl. Phys. Let. 1995, 67,121). Perfluorinated copper phthalocyanine has a mobility of 0.03cm²/V.sec and is generally stable to air operation, but substrates mustbe heated to temperatures above 100° C. in order to maximize themobility in this material (Bao et al. Am. Chem., Soc. 1998, 120, 207).Other n-channel semiconductors, including some based on a naphthaleneframework, have also been reported, but with lower mobilities. One suchnaphthalene-based n-channel semiconductor material,tetracyanonaphthoquino-dimethane (TCNNQD), is capable of operation inair, but the material has displayed a low on/off ratio and is alsodifficult to prepare and purify.

Aromatic tetracarboxylic diimides, based on a naphthalene aromaticframework, have also been demonstrated to provide n-type semiconductors.Thus, in naphthalene diimide-based OFET's in U.S. Pat. No. 6,387,727(Katz et al.) demonstrated n-channel mobilities up to 0.16 cm².V.sec.Comparable results were obtained with bottom contact devices, but athiol underlayer had to be applied between the gold electrodes and thesemiconductor as described. In the absence of the thiol underlayer, themobility of naphthalene diimide derivatives in U.S. Pat. No. 6,387,727was found to be orders of magnitude lower in bottom-contact devices.This patent also discloses fused-ring tetracarboxylic diimide compounds,one example of which is N,N′-bis(4-trifluoromethyl benzyl)naphthalenediimide. The highest mobilities of 0.1 to 0.2 cm²/V.sec were reportedfor N,N′-dioctyl naphthalene diimide.

In a different study, using pulse-radiolysis time-resolved microwaveconductivity measurements, relatively high mobilities have been measuredin films of naphthalene diimides having linear alkyl side chains(Struijk et al., J. Am. Chem. Soc. Vol. 2000, 122, 11057).

U.S. Patent Application Publication 2002/0164835 (Dimitrakopoulos etal.) discloses n-channel semiconductor films made from perylene diimidecompounds, as compared to naphthalene-based compounds, one example ofwhich is N,N′-di(n-1H,1H-perfluorooctyl)perylene diimide. Substituentsattached to the imide nitrogens in the diimide structure comprise alkylchains, electron deficient alkyl groups, and electron deficient benzylgroups, and the chains preferably having a length of four to eighteenatoms. Devices based on materials having a perylene framework used asthe organic semiconductor have low mobilities, for example 10⁻⁵cm²/V.sec for perylene tetracarboxylic dianhydride (PTCDA) and 1.5×10⁻⁵cm²/V.sec for N,N′-diphenyl perylene diimide (PTCDI-Ph) (Horowitz et al.Adv. Mater. 1996, 8, 242 and Ostrick et al. J. Appl. Phys. 1997, 81,6804).

In perylene and naphthalene diimide based OFET's, many experimentalstudies have demonstrated that morphology of the thin film has strongimpact on the device performances. Theoretical calculation andexperimental characterization (particularly X-ray diffraction), haveshown that the molecular packing in PDI is very sensitive to the sidechains (Kazmaier et al. J. Am. Chem. Soc. 1994, 116, 9684). In perylenediimide based n-channel OFET devices, changing the side chain fromn-pentyl to n-octyl increases the field effect mobility of from 0.055cm²/V.sec to 1.3 cm²/V.sec, respectively (Chesterfield et al. J. Phys.Chem. B 2004, 108, 19281). Such sensitivity to the type of side-chain isa manifestation of an aggregation effect and it provides potentially aneffective way to control and optimize the molecular packing for enhancedπ-orbital overlap between neighboring molecules, a necessary forefficient carrier transport. U.S. Pat. No. 7,422,777 (Shukla et al.)discloses N,N′-dicycloalkyl-substituted naphthalene diimide compounds,which in thin films, exhibit optimum packing and exhibit n-channelmobility up to 6 cm²/V.sec in OFET's. U.S. Pat. No. 7,579,619 (Shukla etal.) discloses N,N′-di(arylalkyl) substituted naphthalene diimidecompounds that exhibit high n-channel mobility up to 3 cm²/V.sec intop-contact OFET's.

A variety of naphthalene diimides have been made and tested for n-typesemiconducting properties. In general, these materials, as an n-typesemiconductor, have provided n-channel mobilities up to 6 cm²/V.secusing top-contact configured devices. However, besides charge mobility,improved stability and integrity of the semiconductor layer areimportant goals.

U.S. Patent Application Publication 2005/0176970 (Marks et al.)discloses improved n-channel semiconductor films made of mono- anddiimide perylene and naphthalene compounds wherein the nitrogen and coreare substituted with electron withdrawing groups. Substituents attachedto the imide nitrogen atoms in the diimide structure can be selectedfrom alkyl, cycloalkyl, substituted cycloalkyl, aryl, and substitutedaryl groups. However, this publication fails to suggest any comparativeadvantage of using cycloalkyl groups on the imide nitrogen atoms.Accordingly, mobilities obtained from perylene diimides containing ofN-octyl and N-cyclohexyl are virtually indistinguishable (see Example 10of the publication). Furthermore, the highest mobilities reported inthis reference are 0.2 cm²/V.sec and the reference fails to showexperimental data with respect to naphthalene compounds and require thattheir core be cyano di-substituted.

Aromatic tetracarboxylic diimides, based on a naphthalene and perylenearomatic framework have been widely used as n-type semiconductormaterials (Newman et al. Chem. Mater. 2004, 16, 4436-4451). Relativelylow mobilities have been measured in films of naphthalenetetracarboxylic diimides having linear alkyl side chains usingpulse-radiolysis time-resolved microwave conductivity measurements. SeeStruijk et al. “Liquid Crystalline Perylene Diimides: Architecture andCharge Carrier Mobilities” J. Am. Chem. Soc. Vol. 2000, 122, 11057.However, TFT's based on N,N′-dicyclo-substituted naphthalene diimideexhibit mobility up to 5 cm²/V.sec (Shukla et al. Chem. Mater. 2008, 20,7486-7491). U.S. Pat. No. 6,387,727 (Katz et al.) discloses fused-ringtetracarboxylic diimide compounds, such as N,N′-bis(4-trifluoromethylbenzyl)naphthalene-1,4,5,8,-tetracarboxylic acid diimide. The highestmobilities reported in this patent is between 0.1 and 0.2 cm²/V.sec forN,N′-dioctyl naphthalene-1,4,5,8-tetracarboxylic acid diimide.

It is widely recognized that the morphology and microstructure of anorganic thin film has a strong impact on the charge carrier mobility andOTFT device characteristics. In general, organic materials that formhighly oriented polycrystalline thin films exhibit high charge carriermobility. At the molecular level, it is the basic chemical structure ofthe molecule that controls intermolecular interactions that determinesif a material will be crystalline or amorphous. The extent of π-stackingbetween the molecules determines whether the organic film will be highlycrystalline or totally amorphous. Thus, to have well-defined thin filmmorphology, it is necessary to control materials on the molecular scale.This necessitates adapting the basic structure of semiconductingmolecules in a way that results in an optimum crystalline packingarrangement.

It is known that diimide based semiconductors are very sensitive to thesubstitutions on the nitrogen atoms of the diimide rings. Suchsensitivity to the side-chain is a manifestation of subtle changes indiimide aggregation in solid state and provides potentially an effectiveway to control and optimize the molecular packing for enhanced π-orbitaloverlap between neighboring molecules, a necessity for efficient carriertransport. Accordingly, U.S. Pat. No. 7,422,777 (Shukla et al.)discloses N,N′-dicycloalkyl-substituted naphthalene diimide compounds,which in thin films, exhibit optimum packing and exhibit n-channelmobility up to 6 cm²/V.sec in OFET's. In another example, U.S. Pat. No.7,579,619 (Shukla et al.) discloses N,N′-di(arylalkyl) substitutednaphthalene diimide compounds that exhibit high n-channel mobility up to3 cm²/V.sec in top-contact OFET's. These materials consistently exhibithigher mobility compared to a naphthalene tetracarboxylic diimide havingphenyl substituents.

U.S. Patent Application Publications 2008/0135833 (Shukla et al.) and2009/0256137 (Shukla et al.) describe n-type semiconductor materials forthin film transistors that include configurationally controlledN,N′-dicycloalkyl-substituted naphthalene 1,4,5,8-bis-carboximidecompounds or N,N′-1,4,5,8-naphthalenetetracarboxylic acid imides havinga fluorinated substituent, respectively. In these cycloalkyl-substitutednaphthalene diimide derivatives, the effect of the alkyl groupconfiguration in the cycloalkyl ring affects the aggregation, and hencethe carrier mobility, in solid state.

Recently, dicyanated arylene diimide semiconductors based on peryleneand naphthalene diimide cores have been developed that are solutionprocessable and show environmental stability (Adv. Funct. Mater. 2008,18, 1329-1339). The latter characteristics arise from cyano groupaddition to the core, which increases solubility by decreasing molecularplanarity and stabilizes charge carriers by lowering the energies of thelowest unoccupied molecular orbital's associated with electrontransport. While high temperature vapor deposited devices using thesematerials show good mobilities (ca. 0.1-0.5 cm²/V.sec; Jones et al. Adv.Funct. Mater. 2008, 18, 1329-1339), solution coated device usually givelower mobility and exhibit low I_(on)/I_(off) ratio.

As is clear from the foregoing discussion, the development of newsemiconducting materials, both p-type and n-type, continues to be anenormous topic of interest and unpredictable as to the semiconductiveproperties of various compounds. Among n-type diimide based materials,the highest charge carrier mobility (ca. 5.0 cm²/V.sec) in thin filmtransistors has been observed with N,N′-dicyclohexyl-naphthalenediimide. However, the poor solubility of this material limits itspractical application potential. Although, as discussed above,dicyanated arylene diimide semiconductors based on perylene andnaphthalene diimide cores are solution processable and showenvironmental stability their carrier mobility is low. To attainsolubility extensive molecular modification have to be made whichusually lowers the crystallinity of the material (for example see et al.Adv. Funct. Mater. 2008, 18, 1329-1339) that usually results in lowermobility in OTFT devices.

Efforts continue to improve performance of n-type organic semiconductormaterials in OTFT's and technology for their manufacture and use.Specifically there continues to be research efforts to find newmaterials and processes that are useful in n-type semiconductingmaterials which compounds do not require significant structuralmodification to achieve processability and optimum crystalline packing.

Amic acids are usually more soluble than aromatic anhydrides they arederived from. One attractive way of obtaining solution-processed thinfilms of diimide based semiconductors is to solution coat amic acid and,then by thermal dehydration reaction, convert it to the correspondingdiimide.

The dehydration of amic acids, derived from the reaction of cyclicanhydrides with primary amines, to yield imides is a general method forthe preparation of this important class of heterocyclic compounds and isof major commercial significance in the conversion of polyamic acids topolyimides (Kreuz, Endrey, Gay, and Sroog, J. Polym. Sci., Part A, 4,2607 (1966), and references contained therein.). As polyimides derivedfrom phthalamic acids possess many desirable attributes, this class havematerials have found applications in many technologies ranging fromdielectrics in microelectronics to high temperature adhesives tomembranes (for example see Mittal, Polyimides and Other High TemperaturePolymers: Synthesis, Characterization and Applications vol. 1 to 5).Most of the detailed studies have concentrated on preparation ofpolyphthalamic acids and their conversion to polyimides in solid films(for example, see Kim et al. in Polymer 40, 1999, pp 2263-2270, andreferences cited therein). In contrast, little is known about thedehydration reactions of amic acids derived from anthracene,naphthalene, and perylene anhydrides or anthracene, naphthalene, andperylene tetracarboxylic acid dianhydrides. Fabienne et al have recentlyreported mechanistic studies of polycondensation reactions ofnaphthalene anhydride leading to naphthalimide polymers (Piroux,Mercier, and Picq, High Performance Polymers (2009), 21(5), 624-632).

Genies et al. have reported synthesis of soluble sulfonated naphthalenicpolyimides, derived from naphthalene dianhydride, as materials forproton exchange membranes (Genies et al. Polymer 42 (2001) 359-373).

Copending and commonly assigned U.S. Ser. No. 12/770,803 (filed Apr. 30,2010 by Shukla, Meyer, and Ahearn) describes novel aromatic amic acidsand amic esters that can be thermally converted to corresponding arylenediimides that are formed into semiconductive layers for various articlesand devices. These compounds are advantageous in that the semiconductivelayers can be formed in situ while the precursor compounds are readilycoated from organic solvents.

Salts of poly(amic acids) have also been shown to undergo thermalimidization reaction to generate polyimides. Facinelli et al. haveprepared thermoplastic polyimides via poly(amic acid) salt precursors(see Facinelli et al. Macromolecules 1996, 29, 7342-7350). Thesepoly(amic acid) salts were prepared in heterogeneous reactions of thepoly(amic acid)s using quaternary ammonium bases or triethylaminedissolved in methanol or water to yield soluble salts which were thenmelt imidized in air at 250 or 300° C. for 30 minutes. Ding et al. haveprepared polyimide based membranes from poly(amic acid) salts (see Dinget al. Macromolecules 2002, 35, 905-911). This publication shows thatpoly(amic acid) tertiary amine salts can be quantitatively imidized at alower temperature than the poly(amic acid) or poly(amic acid) quaternaryamine salts of identical backbone structure. Xu et al. have synthesizedpolyimides from a diamine-acid salt and a dianhydride in the presence ofexcess triethylamine, thereby avoiding the use of air-sensitive aromaticdiamine compounds as monomers (Xu et al., Macromol. Rapid Commun. 2000,21, 481-484). Yang et al. have also prepared and characterized poly(amicacid) salts of pyromellitic dianhydride (Yang et al. MacromolecularResearch, 2004, Vol. 12, No. 3, pp 263-268). Polyimide multilayer thinfilms prepared from poly(amic acid) and poly(amic acid) ammonium saltare described in Macromolecular Research, 2008, Vol. 16, No. 8, pp725-733. WO 95/04305 (Flattery et al.) discloses a photosensitivecomposition of a fluorinated poly(amic acid) aminoacrylate salt.

WO 92/00283 (Goze et al.) discloses the use of N,N′-disubstituted amicacid ammonium salts, their use as surfactants, emulsifiers, suspendingagents, and conditioning agents in shampoos. This publication does notteach thermal imidization reaction of such salts. It also fails todisclose amic acids salts of naphthalene or perylene tetracarboxylicacids.

Kim et al., J. Phys. Org. Chem. 2008, 21 731-737 describes the formationof amic acid salts in the hydrolysis of certain aliphatic naphthalenediimides. However, the publication does not isolate these salts or teachtheir thermal imidization reaction. EP 0 805 154A1 (Iwasawa et al.)discloses certain N,N-disubstituted amic acid derivatives as in-vivoinhibitors of protein-farnesyl transferase (PFT).

The use of such amic acid and amic ester precursor compounds have anumber of advantages, as described in the U.S. Ser. No. 12/770,803described above, but there is a need to provide semiconductive layers atlower temperatures, or even at room temperature, to improvemanufacturing processes.

SUMMARY OF THE INVENTION

This invention provides an article comprising a substrate havingdisposed thereon a dry layer that comprises an aromatic, non-polymericamic acid salt. In some embodiments, the dry layer consists essentiallyof the aromatic, non-polymeric amic acid salt, and in other embodiments,the dry layer consists of the aromatic, non-polymeric amic acid salt. Instill other embodiments, the dry layer consists essentially of thearomatic, non-polymeric amic acid salt and an amine catalyst (describedbelow).

This invention also provides articles comprising a gate dielectriclayer, a gate electrode, a source electrode, the dry layer containingthe aromatic, non-polymeric amic acid salt, and a drain electrode,

wherein the dielectric layer, the gate electrode, the dry layercontaining the aromatic, non-polymeric amic acid salt, source electrode,and the drain electrode are in any sequence as long as the gateelectrode and thin organic semiconductor film both contact thedielectric layer, and the source electrode and the drain electrode bothcontact the dry layer of the aromatic, non-polymeric amic acid salt, and

wherein the dry layer of the aromatic, non-polymeric amic acid salt iscontinuous.

For example, the article comprises:

a plurality of the electrically conducting gate electrodes disposed onthe substrate,

the gate dielectric layer disposed on the electrically conducting gateelectrodes,

the dry layer containing the aromatic, non-polymeric amic acid saltdisposed on the dielectric layer substantially overlapping the gateelectrodes, and

a plurality of sets of the source electrodes and drain electrodesdisposed on the dry layer containing the aromatic, non-polymeric amicacid salt such that each of the sets is in alignment with each of thegate electrodes.

The aromatic, non-polymeric amic acid salts described herein can be usedto prepare thin films that are thermally convertible to correspondingsemiconductive arylene diimide compounds, such as, naphthalene diimides.Thus, the arylene diimides are obtained via solid state thermaldehydration imidization reaction of the organic-soluble aromatic,non-polymeric amic acid salts. The aromatic, non-polymeric amic acidsalts can be easily prepared in environmentally friendly solvents likemethanol, ethanol, water, or mixtures thereof.

The advantages of this invention are achieved by preparing thin films ofsemiconducting arylene diimides by solid state thermal dehydrationimidization reaction of an aromatic, non-polymeric amic acid salt or amixture of such salts. The presence of the cation in the salt enableslower temperature conversion to the arylene diimides. In other words,the cation appears to act as a catalyst in the thermal conversionreaction. The low temperature processing combined with readily availablematerials and ease of deposition of thin films over large areas due tosolubility of the aromatic, non-polymeric amic acid salts provide aninexpensive and more convenient approach to the fabrication of thin filmtransistor devices and other semiconductive articles. Furthermore, sincecompared to corresponding diimides, the aromatic, non-polymeric amicacid salts are readily soluble in a variety of solvents and water, thepresent invention enables their coating on a variety of substrateswithout additional preparations (such as applying an extra adhesionpromotion layer onto the substrate or modifying the substrate surface insome other manner).

The present invention and its advantages will become more apparent whentaken in conjunction with the following description, drawings, and theillustrative working examples provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a through 1 d illustrate cross-sectional views of four possibleconfigurations for an organic field effect transistor. FIGS. 1 a and 1 bhave a bottom gate configuration and FIGS. 1 c and 1 d have a top gateconfiguration.

FIGS. 2 a, 2 b, and 3 are graphical plots of data obtained in InventionExample 2 below.

FIGS. 4 a and 4 b are graphical plots of performance data obtained forthe devices described below in Invention Example 2.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

As used herein, “a” or “an” or “the” are used interchangeably with “atleast one,” to mean “one or more” of the components or elements beingdefined. For example, mixtures of aromatic, non-polymeric amic acidsalts can be used to provide mixtures of arylene diimide compounds inthe semiconductive layers or coatings. In addition, “solvent” caninclude mixtures of solvents in which the aromatic, non-polymeric amicacid salts are dissolved or dispersed.

The aromatic, non-polymeric amic acid salts used in this invention are“bis” compounds. By “non-polymeric” in reference to the aromatic,non-polymeric amic acid salts used in the practice of this invention, wemean that the compounds do not contain two or more recurring “bis” unitsin a chain.

Unless otherwise specifically stated, use of the term “substituted” or“substituent” means any group or atom other than hydrogen. Additionally,when the term “group” is used, it means that when a substituent groupcontains a substitutable hydrogen, it is also intended to encompass notonly the substituents unsubstituted form, but also its form to theextent it can be further substituted (up to the maximum possible number)with any other mentioned substituent group or groups (mentioned for thesame position) so long as the substituent does not destroy propertiesnecessary for semiconductor utility. If desired, the substituents canthemselves be further substituted one or more times with acceptablesubstituent groups. When a molecule can have two or more substituents,the substituents can be joined together to form an aliphatic orunsaturated ring unless otherwise provided.

Aromatic, Non-Polymeric Amic Acid Salts and Compositions

n-Channel organic semiconductor layers (or thin films) can include oneor more of arylene diimide compounds. This layer is capable ofexhibiting a field effect electron mobility that is greater than 0.0001cm²/V.sec, or greater than 0.1 cm²/V.sec, or more likely greater than 1cm²/V.sec. In many useful embodiments, the thin organic semiconductorfilms (and the devices containing the films) exhibit a field effectelectron mobility that is greater than 0.10 cm²/V.sec.

In addition, the n-channel organic semiconductor film is capable ofproviding on/off ratios of a source/drain current of at least 10³ ortypically of at least 10⁵. The on/off ratio is measured as themaximum/minimum of the drain current as the gate voltage is swept fromzero to 100 volts and the drain-source voltage is held at a constantvalue of 100 volts, and employing a gate dielectric.

Moreover, these properties are attainable after repeated exposure of then-type organic semiconducting layer to air before layer deposition aswell as exposure of the thin film transistor device or the channel layerto air after layer deposition.

Without wishing to be bound by theory, there are several factors thatare believed to contribute to the desirable properties of the organicsemiconductor layer containing arylene diimides compounds. Thesolid-state structure of the arylene diimide compounds described hereinexhibit good order in the layer. The molecules are packed such that theorbitals of the conjugated arylene core system containing the arylenering system or the imide carboxyl groups are able to interact withadjacent molecules, resulting in high mobility. The direction of thisinteraction has a component parallel to the direction of desired currentflow in a device using this material in the semiconductor layer. Themorphology of the layer formed by arylene diimides is substantiallycontinuous such that current flows through the material withoutunacceptable interruption. However, it is particularly advantageous thatthe arylene diimide layer is not only continuous but also exhibitspolycrystalline morphology with minimum inter-grain defects so thatcurrent flows through the material without unacceptable interruption.The stereochemistry of the substituent on the arylene diimides is suchthat they do not disrupt the intrinsic ability of these molecules topack in an effective crystalline arrangement.

The lowest lying unoccupied molecular orbital of the arylene diimidecompound is at an energy that allows for injection of electrons in thecompound at useful voltages from metals with reasonable work functions.Arylene diimides (such as naphthalene diimides and perylene diimides)described herein have a desirable lowest unoccupied molecular orbital(LUMO) energy level of about 3.0 eV to about 4.6 eV with reference tothe vacuum energy level. As known in the art, LUMO energy level andreduction potential approximately describe the same characteristics of amaterial. LUMO energy level values are measured with reference to thevacuum energy level, and reduction potential values are measured insolution versus a standard electrode. An advantage for thin filmtransistor devices is that the LUMO in the crystalline solid, which isthe conduction band of the organic semiconductor, and the electronaffinity of the solid both are measured with reference to the vacuumlevel. The latter parameters are usually different from the formerparameters, which are obtained from solution.

As indicated above, the organic solvent-soluble compositions describedherein comprise one or more aromatic, non-polymeric amic acid salts thatcan be converted with thermal energy at relatively low temperatures toprovide organic semiconductor compositions having one or more of thecorresponding arylene diimides compounds. In many embodiments, theorganic layer consists essentially of the one or more aromatic,non-polymeric amic acid salts, meaning that no other components arepresent that are essential to the invention. Still other embodimentshave thin film layers that consist only of the one or more aromatic,non-polymeric amic acid salts.

The aromatic, non-polymeric amic acid salts used in this invention offerseveral advantages. For example, since the aromatic, non-polymeric amicacid salts are soluble in a number of organic solvents, and they can bedeposited on the surface of a given substrate from a suitable organicsolvent solution without any additional surface preparation (forexample, surface energy matching). In cases where the substrate ispolymeric, the solutions can be prepared using organic solvents ormixtures of solvents that do not have unfavorable or undesirableinteraction (for example, swelling) with the substrate. As noted above,the aromatic, non-polymeric amic acid salts can be quickly and easilyconverted to the arylene diimides at relatively low temperatures due tothe presence of the catalytic cation portion of the salt.

Thus, the aromatic, non-polymeric amic acid salts have a suitable amicacid anion and one or more suitable cations. Useful cations can beorganic or inorganic although the organic cations are generally bestbecause they are more readily decomposable during thermal conversion ofthe aromatic, non-polymeric amic acid salts to the corresponding arylenediimides. Useful inorganic cations include but are not limited to,alkali metal ions.

A number of organic cations can be used as counter ions to amic acidsalt anions. Useful organic cations include but are not limited to,sulfonium, ammonium, phosphonium, arsenonium, morpholinium, pyridinium,quinolinium ions, and other organic cations that would be apparent toone skilled in the art. Quaternary ammonium ions having one to fourhydrogen atoms are particularly useful and one to three valences of thecation can be filled with the same or different organic substituentssuch as alkyl, cycloalkyl, aryl, heteroaryl, fluoroalkyl, orheterocyclyl groups. In most embodiments, the ammonium cations have atleast 2 hydrogen atoms and up to two alkyl or cycloalkyl groups. Instill other embodiments, the ammonium cations have three or fourhydrogen atoms and optionally one alkyl group (such as a methyl or ethylgroup) or aryl group (such as a phenyl group).

In many embodiments, the aromatic, non-polymeric amic acid salts arerepresented by either the following Structure (I) or (II):

wherein: Ar is an anthracene, naphthalene, or perylene nucleus and thefour carbonyl groups are attached directly to peri carbon atoms, thenon-cation A₁, A₂, and A₃ groups are independently aryl, heteroaryl,non-aromatic alkyl, alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclylgroups, and the four A₁ groups in the cations represent the same ordifferent hydrogen atom or aryl, heteroaryl, non-aromatic alkyl,alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclyl groups, provided atleast one of the A₁ cation groups is a hydrogen atom.

More specifically, Ar is a substituted or unsubstituted anthracene,naphthalene, or perylene nucleus and the four carbonyl groups areattached directly to peri carbon atoms.

The non-cation A₁, A₂, and A₃ groups can be a substituted orunsubstituted aryl group having 6 or 14 carbon atoms in the aromaticring (such as substituted or unsubstituted phenyl or naphthyl groups), aheteroaryl group having 5 to 10 carbon and heteroatoms (such asnitrogen, oxygen, and sulfur) in the aromatic ring (such as substitutedor unsubstituted thienyl, furanyl, pyridyl, pyrrolyl, and pyrazolylgroups), a branched or linear, substituted or unsubstituted alkyl grouphaving 1 to 18 carbon atoms and including substituted or unsubstitutedfluoroalkyl groups (such as CF₃ or C₃F₇) and alkylaryl groups (suchbenzyl groups), a substituted or unsubstituted cycloalkyl group at least4 carbon atoms in the carbocyclic ring, or a substituted orunsubstituted heterocyclyl group having 5 to 10 carbon and heteroatoms(such as nitrogen, oxygen, and sulfur) in the heterocyclic ring.

The cation A₁ groups can be hydrogen or independently any of the groupsdefined above for the non-cation A₁, A₂, and A₃.

Various substituents on these Ar, A₁, A₂, and A₃ groups would be readilyapparent to one skilled in the art but can include for example, alkylgroups having 1 to 6 carbon atoms (such as methyl, ethyl, pentyl, andhexyl groups), cyano, fluoro, and fluoroalkyl groups (such as CF₃).

In many embodiments, Ar is naphthalene or perylene, the non-cation A₁,A₂, and A₃ groups are independently alkyl, fluoroalkyl, alkylphenyl,phenyl, or cycloalkyl groups, which can be substituted or unsubstituted,and the four A₁ groups in the cations represent the same or differenthydrogen or alkyl, fluoroalkyl, alkylphenyl, phenyl, or cycloalkylgroups, which can also be substituted, provided that at least three ofthe A₁ cation groups are hydrogen atoms.

For example, Ar can be a substituted or unsubstituted naphthalene orperylene, and A₁, A₂, and A₃ can be independently a substituted orunsubstituted alkyl, substituted or unsubstituted fluoroalkyl,substituted or unsubstituted alkylaryl, substituted or unsubstitutedphenyl, or substituted or unsubstituted cycloalkyl group. More likely,Ar is perylene, and A₁, A₂, and A₃ are independently a substituted orunsubstituted alkyl group of 1 to 12 carbon atoms, phenyl, substitutedor unsubstituted (C₁-C₃)alkylphenyl, substituted or unsubstitutedcyclopentyl, or substituted or unsubstituted cyclohexyl group.

In still other embodiments, Ar is naphthalene or perylene and the fourA₁ cation groups are hydrogen atoms.

For all of the Structures (I), (II), (Ia), (Ib), (IIa), and (IIb)described herein, some of the desired alkylaryl groups are described inU.S. Pat. No. 7,579,619B2 (Shukla et al.) and U.S. Pat. No. 7,198,977B2(Shukla et al.) that are incorporated herein by reference. Somedesirable fluorinated aryl groups are described in U.S. Pat. No.7,326,956B2 (Shukla et al.) that is also incorporated herein byreference.

Some desirable cycloalkyl groups are described in U.S. Pat. No.7,422,777B2 (Shukla et al.) and U.S. Pat. No. 7,649,199B2 (Shukla etal.) that are incorporated herein by reference. Some desirable arylgroups are described in U.S. Pat. No. 7,629,605B2 (Shukla et al.) thatis incorporated herein by reference.

More specifically, some of the aromatic, non-polymeric amic acid saltsused in this invention are represented by the following Structure (Ia)or (IIa):

wherein: Ar and the non-cation A₁, A₂, and A₃ groups are as definedabove, and the three A₁ groups in the cations represent the same ordifferent hydrogen atom or aryl, heteroaryl, non-aromatic alkyl,alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclyl groups, as definedabove, provided at least one of the A₁ cation groups is a hydrogen atom.

Still again, the aromatic, non-polymeric amic acid salts used in thisinvention can be represented by the following Structure (Ib) or (IIb):

wherein: Ar and the non-cation A₁, A₂, and A₃ groups are as definedabove, and the A₁ group in the cations represent a hydrogen atom or anaryl, heteroaryl, non-aromatic alkyl, alkylaryl, fluoroalkyl,cycloalkyl, or heterocyclyl groups.

In some embodiments of the Structure IIa and IIb compounds, Ar isnaphthalene or perylene, the non-cation A₁, A₂, and A₃ groups are thesame or different alkyl, fluoroalkyl, alkylphenyl, phenyl, or cycloalkylgroups, the cation A₁ group is a hydrogen atom or an alkyl group having1 to 18 carbon atoms (including a methyl or ethyl group).

Examples of aromatic, non-polymeric amic acid salts used in the practiceof this invention are those listed below as Compounds I-1 through I-58,all of which can be thermally converted to the corresponding arylenediimides:

The aromatic, non-polymeric amic acid salts can be easily prepared in asimple reaction scheme, and the syntheses of several compounds aredescribed below in the Invention Examples.

Aromatic, non-polymeric, amic acid salts of Structure Ib can be preparedby a simple, one-step reaction scheme shown in the following Equation 1:

For example, bis-naphthalamic acid can be prepared by reacting anappropriate amine (such as a primary amine) with naphthalene dianhydrideor the corresponding naphthalene tetracarboxylic acid with astoichiometric excess (at least 4 equivalents) of an appropriate amineat ambient temperature in a suitable solvent or mixture of solvents. Theamine is provided in a stoichiometric “excess” beyond that needed tocompletely use up the amine to form an aromatic, non-polymeric amic acidsalt. The excess amine in the reaction will create an aromatic,non-polymeric amic acid salt. Similar reactions can be easily carriedout using other bisanhydrides and carboxylic acids.

In another method, the aromatic, non-polymeric amic acid salt ofStructure Ia can be prepared by preparing the corresponding bis amicacid followed by reaction with 2 equivalents of an appropriate amine tomake the aromatic, non-polymeric amic acid salt according to thefollowing Equation 2:

A number of organic solvents can be used for the reactions of thetetracarboxylic acid or dianhydride with the excess amine, and thechoice of solvent is not particularly limited so long as it dissolvesthe aromatic, non-polymeric amic acid salt product. Solubility of thearomatic, non-polymeric amic acid salt depends on the nature ofassociated cation and can be controlled by modifying the counter cation.Specific examples of useful solvents for preparing amic acid saltsinclude, but not limited to, methanol, ethanol, n-propanol, n-butanol,N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine,dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone,tetrahydrofuran, chloroform, methylene chloride, dichloroethane,acetone, ethyl methyl ketone, cyclopentanone, cyclohexanone, andanisole. These solvents can be used alone or in combination. In someinstances, even an organic solvent in which the aromatic, non-polymericamic acid salt is precipitated can be used.

The aromatic, non-polymeric amic acid salt can be present in thecomposition used in this invention in an amount of at least 0.5 weight %and up to and including 100 weight %, or from 0.5 weight % to 50 weight%. This weight % can be considered “% solids” in the compositions thatare in solution form.

In the preparation of the aromatic, non-polymeric amic acid salts, boththe cis and trans isomers of the aromatic, non-polymeric amic acid saltscan be formed (see the following Equation 3).

The relative amounts of cis and trans isomers depends on a number offactors such as reaction solvent, temperature, concentration of amine,and the presence or absence of additional catalyst.

To facilitate the reaction of the tetracarboxylic acid or dianhydridewith the amine in the organic solvent, the amine can be dispersed ordissolved in the organic solvent, under stirring, and thetetracarboxylic acid or dianhydride is then added, as it is or afterdispersing or dissolving it in the organic solvent. Alternatively, theamine can be added to a solution of the tetracarboxylic dianhydride thatis dispersed or dissolved in the organic solvent. In still anothermethod, the tetracarboxylic dianhydride and the amine can be addedsimultaneously to the organic solvent. In addition, the two reactantscan be added alternatively to the organic solvent until all of thedesired amounts are in the solution or dispersion. Stirring or othersuitable agitation can be desirable to obtain a solution or dispersionof the reactants. A skilled worker would understand that still otherprocedures can be used to obtain the desired reaction product (aromatic,non-polymeric amic acid salt).

For the preparation of the aromatic, non-polymeric amic acid salts ofStructure Ib, the molar ratio of the amine reactant (that is, the totalmoles of the amine to the tetracarboxylic acid or dianhydride) isgenerally at least 4:1, or at least 5:1, or more likely at least 6:1.For the preparation of the aromatic, non-polymeric amic acid salts ofStructure IIb, the molar ratio of the amine reactant (that is, the totalmoles of the amine to the tetracarboxylic acid or dianhydride) isgenerally at least 2:1, or at least 2.2:1, or more likely at least2.5:1.

For the preparation of the aromatic, non-polymeric amic acid salts ofStructure Ia (as depicted in Equation 2), the molar ratio of the aminereactant (that is, the total moles of the amine to the tetracarboxylicacid or dianhydride) in Step 1 is generally at least 2:1, or at least2.2:1, or more likely at least 2.5:1. In the Step 2 for the preparationof the aromatic, non-polymeric amic acid salts of Structure Ia, themolar ration of the amine reactant (that is, the total moles of theamine to the amic acid) is generally 2:1, or at least 3:1, or morelikely at least 4:1.

Depending on the nature of the amine and dianhydride or carboxylic acid,the described synthesis of the aromatic, non-polymeric amic acid saltcan be carried out at very low temperatures (from −20° C. to 0° C.), atroom temperature, or at a higher temperature of from 25° C. to 100° C.The reaction of bisanhydride with the amine according to Equation 1proceeds to give the aromatic, non-polymeric amic acid salt in highyield. For this reason, the reaction can easily be scaled up to anydesired concentration. Accordingly, the concentration of the resultingproduct is generally from 1 to 50 wt. % or from 5 to 30 weight % or evenfrom 1 to 10 weight % in the reaction solution or dispersion. Thereaction can be carried out at a high concentration in the initialstage, and thereafter, more organic solvent, water, or both, can beadded to the reaction solution or dispersion to adjust theconcentration.

The aromatic, non-polymeric amic acid salt is easily converted to thecorresponding arylene diimide compound by thermal dehydration imidationring closure reaction. The temperature of the dehydration imidation ringclosure is dependent on the structure of the aromatic, non-polymericamic acid salt. However, the thermal imidation of the aromatic,non-polymeric amic acid salt in a thin film transistor device or otherarticle is generally carried out in the solid state at a temperature offrom 100° C. and up to about 400° C., or from about 120° C. to about250° C.

It can be advantageous to carry out the dehydration imidation ringclosure reaction of aromatic, non-polymeric amic acid salt in thepresence of an added catalyst in the reaction solution or dispersions.Such catalysts include be are not limited to basic catalysts such asamines such as a tertiary amine or aromatic amine. Such tertiary aminesand aromatic amines include but are not limited to, pyridine,triethylamine, tributylamine, trimethylamine, tripropylamine,diazabicyclo[1.1.1]octane, diazabicycloundecane, and trioctylamine.Mixtures of these compounds can also be used. Catalytic imidation thatproceeds at a relatively low temperature is particularly desirable. Sucha tertiary amine or aromatic amine can be present in an amount of atleast 0.5 weight % and up to and including 10 weight %, or more likelyfrom about 0.5 to about 2 weight %, based on the amic acid salt that isto be thermally converted. Thus, the composition of this invention canconsist essentially of an aromatic, non-polymeric amic acid salt and anamine such as a tertiary amine.

A thin film of an arylene diimide compound can be prepared with a methodcomprising the steps of:

-   -   A) adding a dianhydride (as described above) to an organic        solvent (described above) and stirring the resulting mixture to        obtain a solution or dispersion,    -   B) adding an amine to the dianhydride solution or dispersion to        provide a molar ratio of the amine to the dianhydride of at        least 4:1 and mixing the reactants to obtain an arylene diimide        precursor that is an aromatic, non-polymeric amic acid salt,    -   C) adding a tertiary amine to the aromatic, non-polymeric amic        acid salt solution obtained in step B,    -   D) applying salt solution of Step C to a suitable substrate (as        described below and particularly a metal, silicon, plastic film,        glass sheet, or coated glass) to form a coating,    -   E) removing the organic solvent from the coating to form a thin        film of the aromatic, non-polymeric amic acid salt, and    -   F) thermally converting (as described above) the aromatic,        non-polymeric amid acid salt precursor in the thin film to an        arylene diimide compound to form an organic semiconductor layer        that is generally a thin film of from about 100 to about 1000        Angstroms in dry thickness.

The solvent, or mixture of solvents, can be removed in step E using anysuitable technique and equipment. Generally, the solvents are removedfrom the coating by a suitable evaporation technique at desired time andtemperature. Higher temperatures can be used in shorted times, but itdepends upon the vapor pressure of the organic solvents.

For example, a thin film of an arylene diimide compound can be preparedwith a method comprising the steps of:

-   -   A) adding a dianhydride (as described above) to an organic        solvent (described above) and stirring the resulting mixture to        obtain a solution or dispersion,    -   B) adding an amine to the dianhydride solution or dispersion to        provide a molar ratio of the amine to the dianhydride of at        least 4:1 and mixing the reactants to obtain an arylene diimide        precursor that is an aromatic, non-polymeric amic acid salt,    -   C) adding a tertiary amine to the aromatic, non-polymeric amic        acid salt solution obtained in Step B,    -   D) applying salt solution of Step C to a suitable substrate (as        described below and particularly a metal, silicon, plastic film,        glass sheet, or coated glass) to form a coating,    -   E) removing the organic solvent from the coating to form a thin        film of the aromatic, non-polymeric amic acid salt, and    -   F) thermally converting (as described above) the aromatic,        non-polymeric amid acid salt in the thin film to an arylene        diimide compound to form an organic semiconductor layer that is        generally a thin film of from about 100 to about 1000 Angstroms        in dry thickness.

The solvent, or mixture of solvents, can be removed in step E using anysuitable technique and equipment. Generally, the solvents are removedfrom the coating by a suitable evaporation technique at desired time andtemperature. Higher temperatures can be used in shorted times, but itdepends upon the vapor pressure of the organic solvents.

A method for preparing a thin film of an amic acid salt also comprisesthe steps of:

-   -   A) adding a dianhydride to an organic solvent and stirring the        resulting mixture to obtain a solution or dispersion,    -   B) adding an amine to the dianhydride solution or dispersion to        provide a molar ratio of the amine to the dianhydride of at        least 4:1 and mixing the reactants to obtain an arylene diimide        precursor that is an aromatic, non-polymeric amic acid salt,    -   C) applying the amic acid salt solution to a substrate (as        described below) to form a coating (or thin film), and    -   D) removing the organic solvent from the coating to form a layer        (or thin film) of the aromatic, non-polymeric amic acid salt,        for example by evaporation or other technique as described        above.

The resulting thin film of the aromatic, non-polymeric amic acid salt(or mixture of aromatic, non-polymeric amic acid salts) can then befurther processed or used in a suitable manner before it is thermalconverted to the corresponding arylene diimide compound.

More particularly, a method comprises, not necessarily in order, thefollowing steps:

-   -   A) providing an electrically conductive substrate (as described        below),    -   B) providing a gate electrode material over the substrate,    -   C) providing a gate dielectric over the gate electrode material,    -   D) depositing a organic solvent solution or dispersion of an        aromatic, non-polymeric amic acid salt over the gate dielectric,        and    -   E) evaporating the organic solvent to produce a thin film of the        aromatic, non-polymeric amic acid salt.

Thin films of the aromatic, non-polymeric amic acid salt can be cast orcoated from solution in which they are prepared and they can beconverted to the arylene diimide compound as a thin film by simplyheating the substrate on which it is coated.

The aromatic, non-polymeric amic acid salt can be applied or depositedonto a suitable support using any suitable technique and equipment. Forexample, it can be applied out of the solution using solution coatingtechniques (such as spin or hopper coating), solution-phase deposition,ink jet techniques, lithographic or flexographic deposition in desiredpatterns, or spray coating.

For example, the aromatic, non-polymeric amic acid salt can be thermallyconverted to the arylene diimide compound to exhibit a field effectelectron mobility that is greater than 0.0001 cm²/V.sec.

In addition, the aromatic, non-polymeric amic acid salt can be depositedto provide an amount of at least 98 weight % and up to 100 weight %based on total dry layer weight. For example, it can be deposited on thesubstrate by solution-phase deposition wherein the substrate has atemperature of no more than 250° C. during deposition. The depositionsolution can include one or more organic solvents.

Alternatively, the aromatic, non-polymeric amic acid salt can bedeposited in an organic solvent solution comprising from about 0.5 toabout 10 weight % of the aromatic, non-polymeric amic acid salt.

Thermal Conversion of Precursor to Semiconductive Compound

The thermal conversion can be carried out using various procedures andapparatus to supply the desired thermal energy (or heat) to the amicacid salt that is on a substrate. For example, the desired thermalenergy can be provided by one or more lasers such as those emittinginfrared radiation, microheaters, microwave heaters, and other heatingdevices that would be readily apparent to one skilled in the art. Thethermal energy can be applied in a uniform manner over the entireapplied coating of aromatic, non-polymeric amic acid salt, or thethermal energy can be applied patternwise to convert only a pattern ofthe coating, and the non-converted coating can then be removed in asuitable fashion (for example, by washing with a solvent in which it issoluble). As noted above, an advantage of this invention is that thearomatic, non-polymeric amic acid salts can be thermally converted atrelatively lower temperatures compared to the thermal conversiontemperatures of corresponding amic acids or amic esters.

Electronic Devices

The organic semiconductor composition described herein, when used in theform of an n-channel layer, can exhibit high performance under inertconditions as well as in air without the need for special chemicalunderlayers.

The electronic devices of this invention can comprise the thin film ororganic semiconductor layer as described above. The electronic devicescan include, but are not limited to, an organic field effect transistor(OFET), organic light emitting diode (OLED), photodetector, sensor,logic circuit, memory element, capacitor, and photovoltaic (PV) cell.For example, the active semiconductor channel between the drain andsource in an OFET can comprise the organic semiconducting layer. Asanother example, an electron injection or transport layer in an OLEDdevice-can comprise the organic semiconducting layer. The amic acid saltcompositions and organic semiconductor layers formed there from haveparticular utility in OFET's.

Thus, the aromatic, non-polymeric amic acid salts used in the practiceof this invention can be used in a process for the production ofsemiconductor components and electronic devices incorporating suchcomponents. In one embodiment, a substrate is provided and a layer ofthe aromatic, non-polymeric amic acid salt composition can be applied tothe substrate and electrical contacts made with the layer. The exactprocess sequence is determined by the structure of the desiredsemiconductive article. Thus, in the production of an organic fieldeffect transistor, for example, a gate electrode can be first depositedon a flexible substrate, for example an organic polymer film, the gateelectrode can then be insulated with a dielectric and then source anddrain electrodes and a layer of the aromatic, non-polymeric amic acidsalt can be applied on top and then thermally converted to an n-channelsemiconductor layer containing the corresponding arylene diimidecompound. The structure of such a thin film transistor and hence thesequence of its production can be varied in the customary manner knownto a person skilled in the art. Thus, alternatively, a gate electrodecan be deposited first, followed by a gate dielectric, then thearomatic, non-polymeric amic acid salt layer can be applied, and finallythe contacts for the source electrode and drain electrode deposited onthe precursor layer, which is then thermally converted to an organicsemiconductor layer containing the corresponding arylene diimidecompound. A third structure could have the source and drain electrodesdeposited first, then the aromatic, non-polymeric amic acid salt layer,with dielectric and gate electrode, is deposited on top. This layer canthen be thermally converted in a suitable manner to provide the organicsemiconductor arylene diimide compound.

The skilled artisan will recognize other structures can be prepared orintermediate surface modifying layers can be interposed between theabove-described components of a thin film transistor device of thisinvention. In most embodiments, a field effect thin film transistordevice comprises an insulating layer, a gate electrode, an organicsemiconductor layer comprising an organic semiconducting arylene diimidecompound (thermally converted from the aromatic, non-polymeric amic acidsalt) as described herein, a source electrode, and a drain electrode,wherein the insulating layer, the gate electrode, the organicsemiconductor layer, the source electrode, and the drain electrode arein any sequence as long as the gate electrode, and the organicsemiconductor layer both contacts the insulating layer, and the sourceelectrode and the drain electrode both contact the organic semiconductorlayer.

Substrate

A substrate (also known herein as a support) can be used for supportingthe aromatic, non-polymeric amic acid salt that is convertible to anorganic semiconductor thin film during manufacturing, testing, or use.The skilled artisan will appreciate that a substrate selected forcommercial embodiments can be different from one selected for testing orscreening various embodiments. In other embodiments, a substrate can bedetachably adhered or mechanically affixed to a substrate, such as whenthe substrate is desired for a temporary purpose. For example, aflexible polymeric substrate can be adhered to a rigid glass support,which support could be removed. In some embodiments, the substrate doesnot provide any necessary electrical function for the FET. This type ofsubstrate is considered a “non-participating substrate”.

Useful substrate materials can include organic or inorganic materials.For example, the substrate can comprise inorganic glasses, ceramicfoils, polymeric materials, filled polymeric materials, coated metallicfoils, acrylics, epoxies, polyamides, polycarbonates, polyimides,polyketones,poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene)[sometimes referred to as poly(ether ether ketone) or PEEK],polynorbornenes, polyphenyleneoxides, poly(ethylenenaphthalenedicarboxylate) (PEN), poly(ethylene terephthalate) (PET),poly(phenylene sulfide) (PPS), and fiber-reinforced plastics (FRP).

A flexible substrate is used in some embodiments to allow for rollprocessing, which can be continuous, providing economy of scale andeconomy of manufacturing over flat or rigid substrates. The flexiblesubstrate chosen is capable of be wrapped around the circumference of acylinder of less than about 50 cm diameter, typically less than 25 cmdiameter, or even less than 10 cm diameter, without distorting orbreaking, using low force such as by unaided hands. The flexiblesubstrate can be rolled upon itself.

In some embodiments of this invention, the substrate is optional. Forexample, in a top construction as in FIG. 1 b, when the gate electrodeor gate dielectric provides sufficient substrate for the intended use ofthe resultant TFT, the substrate is not required. In addition, thesubstrate can be combined with a temporary support. In such anembodiment, a substrate can be detachably adhered or mechanicallyaffixed to the substrate, such as when the substrate is desired for atemporary purpose, for example, manufacturing, transport, testing, orstorage. For example, a flexible polymeric substrate can be adhered to arigid glass support, which flexible substrate can be removed.

Gate Electrode

The gate electrode can be any useful conductive material. A variety ofgate materials known in the art, are also suitable including metals,degenerately doped semiconductors, conducting polymers, and printablematerials such as carbon ink or silver-epoxy. For example, the gateelectrode can comprise doped silicon, or a metal, such as aluminum,chromium, gold, silver, nickel, palladium, platinum, tantalum, andtitanium. Conductive polymers also can be used, for example polyaniline,poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS). Inaddition, alloys, combinations, and multilayers of these materials canbe useful.

In some embodiments, the same material can provide the gate electrodefunction and also provide a support function. For example, doped siliconcan function as the gate electrode and support the OFET.

Gate Dielectric

The gate dielectric is provided on the gate electrode to electricallyinsulate the gate electrode from the balance of the OFET device. Thegate dielectric can be provided in the OFET as a separate layer, orformed on the gate such as by oxidizing the gate material to form thegate dielectric. The dielectric layer can comprise two or more layershaving different dielectric constants.

The gate dielectric should have a suitable dielectric constant that canvary widely depending on the particular device and circumstance of use.For example, a dielectric constant from about 2 to about 100 or evenhigher is known for a gate dielectric. The gate dielectric layer shouldhave a resistivity of 10¹⁴ ohm-cm or greater in OFET applications. Thegate dielectric can comprise organic polymeric materials, inorganicmaterials, and organic-inorganic composite materials. Useful polymermaterials for the gate dielectric can comprise one or more dielectricpolymers such as acrylic and styrenic polymers selected from the groupconsisting of: acrylic, styrenic and styrenic-acrylic latexes,solution-based acrylic, styrenic and styrenic-acrylic polymers, andcombinations thereof; heteroatom-substituted styrenic polymers selectedfrom the group consisting of: partially hydrogenatedpoly(4-hydroxy)styrene, poly(4-hydroxy)styrene, and copolymers ofpoly(4-hydroxy)styrene with hydroxyethyl (meth)acrylate, alkyl(meth)acrylate, styrene, and alkyl-substituted styrene wherein the alkylgroup is a C₁ to C₁₈ straight or branched chain alkyl group,phenol-aldehyde (co)polymers and (co)oligomers and combinations thereof.The gate dielectric can comprise a polymeric material, such aspoly(vinylidene difluoride) (PVDF), cyanocelluloses, polyimides, andothers known in the art. The gate electric can comprise a plurality oflayers of different materials having different dielectric constants.

In certain embodiments, polymer gate dielectric can possess one or moreof the following characteristics: coatable out of solution,crosslinkable, photo-patternable, high thermal stability (for example,stable up to a temperature of about 250° C.), low processingtemperatures (for example, less than about 150° C. or less than 100°C.), and are compatible with flexible substrates. Crosslinkable orphoto-patternable polymers are particularly desirable. This is becausethey provide flexibility in manufacturing methods, would easilyintegrate with solution processed device layers, and could allow forhigh-speed roll-to-roll processing. Polymers are photo-patternable ifthey include one or more crosslinking (that is, crosslinkable) groupsthat can be induced to form a crosslinked network upon exposure toradiation (most commonly, UV radiation). The exposed (crosslinkedportion of the polymer) becomes insoluble in certain solvents and theunexposed portion of the polymer can be washed away using a developingsolvent. This is an example of a negative-acting photo-patternablepolymer. It is also possible to photo-pattern a polymer that isinitially insoluble in certain solvents and that becomes soluble inUV-exposed areas upon exposure. This is an example of a positive-actingphoto-patternable polymer.

For OFET's, the polymeric dielectric layer generally has a thickness ofless than about 5000 Angstroms (Å), typically less than about 3000 Å, orless than about 2000 Å. The polymeric dielectric layer generally has athickness of at least about 500 Å or typically at least about 1000 Å.The thickness can be determined through known methods such asellipsometry and profilometry. For embedded capacitors and printedcircuit board applications, the thickness can include those describedabove for OFET's, but can also be at least 10 μm or at least 20 μm.

The term dielectric polymers herein encompasses homopolymers, copolymersderived from polymerization of two or more monomers, post-derivatized(co)polymers including graft (co)polymers, and low molecular weighthomopolymers or copolymers. The polymers can be linear, branched,hyperbranched, or dendritic.

Useful materials for the gate dielectric can comprise, for example, aninorganic electrically insulating material. Specific examples ofmaterials useful for the gate dielectric include strontiates,tantalates, titanates, zirconates, aluminum oxides, silicon oxides,tantalum oxides, titanium oxides, silicon nitrides, barium titanate,barium strontium titanate, barium zirconate titanate, zinc selenide, andzinc sulfide. In addition, alloys, combinations, and multilayers ofthese materials can be used for the gate dielectric. In addition,polymeric materials such as polyimides and insulators that exhibit ahigh dielectric constant are also suitable dielectric materials asdescribed in U.S. Pat. No. 5,981,970 (Dimitrakopoulous et al.).

Useful dielectric polymers include acrylic, styrenic, andstyrenic-acrylic latexes comprising alkyl (meth)acrylate, styrene, andalkyl-substituted styrene wherein the alkyl group is a C₁ to C₁₈straight or branched chain alkyl group. Useful optional monomers used toderive these latex-based polymers include (meth)acrylic acid,hydroxyethyl (meth)acrylate, and glycidyl (meth)acrylate. Such latexesare selected from the group: Latexes A, defined herein as one or morelatex resins comprising at least 85 weight % or at least 90 weight % ofalkyl (meth)acrylate, styrene, and alkyl-substituted styrene. Usefuladditional monomers used to derive these latex resins include(meth)acrylic acid (up to 5 weight %), hydroxyethyl (meth)acrylate (upto 10 weight %), and glycidyl (meth)acrylate (up to 5 weight %). Suchlatexes generally have an average particle size of less than about 150nm or less than about 100 nm.

Particularly useful dielectric polymers with high resistivity (above10¹⁴ ohm-cm) are Acrylic Latexes B and Styrene-Acrylic Latexes C andcombinations thereof. Acrylic Latexes B are defined herein as one ormore acrylic latexes comprising at least 85 weight % or at least 90weight % of methyl methacrylate or butyl acrylate or both.Styrene-Acrylic Latexes C are defined herein as one or morestyrene-acrylic latexes comprising at least 85 weight % or at least 90weight % of methyl methacrylate, butyl acrylate, or styrene, or mixturesthereof. Useful additional monomers used to derive Acrylic Latexes B andStyrene-Acrylic Latexes C include (meth)acrylic acid (up to 5 weight %),hydroxyethyl methacrylate (up to 10 weight %), and glycidyl methacrylate(up to 5 weight %). Commercial examples of acrylic and styrenic acryliclatexes useful as dielectric polymers include Joncryl® 95 and 1915(co)polymers (Johnson Polymer). Methods for synthesizing suitable latexpolymers have been reported in WO 03/099574 (Caspar et al.).

Further useful dielectric polymers include solution-based acrylic,styrenic and styrenic-acrylic polymers. Herein the term “solution-based”refers to materials that are soluble in solvents such as water or one ormore common organic solvents including alcohols, ethers, esters,ketones, and aromatic hydrocarbons. Such solution-based acrylic,styrenic and styrenic-acrylic polymers have a Mw of less than 100,000and an acid number less than about 250.

Useful dielectric polymers also include heteroatom-substituted styrenicpolymers selected from the group consisting of: partially hydrogenatedpoly(4-hydroxy)styrene, poly(4-hydroxy)styrene (PHS), and copolymers ofPHS with hydroxyethyl (meth)acrylate, alkyl (meth)acrylate, styrene, andalkyl-substituted styrene wherein the alkyl group is a C₁ to C₁₈straight or branched chain alkyl group. When a PHS homopolymer is used,the branched structure is desired and the (co)polymers have an Mw ofless than about 30,000. Partially hydrogenated PHS refers to PHSpolymers that have been hydrogenated up to about 50 equivalent % of theunsaturation within the polymer. Commercial examples include PHS-B(branched PHS homopolymer; DuPont Electronic Technologies, Dallas,Tex.), Maruka Lyncur CMM (PHS copolymer with methyl methacrylate;Maruzen Petrochemical Co., LTD. Tokyo, Japan), Maruka Lyncur CHM (PHScopolymer with hydroxyethyl methacrylate; Maruzen), Maruka Lyncur CBA(PHS copolymer with butyl acrylate, Maruzen), Maruka Lyncur CST 15, 50,and 70 (PHS copolymers with styrene, Maruzen), and Maruka Lyncur PHM-C(partially hydrogenated PHS, Maruzen).

Other useful dielectric polymers include phenol-aldehyde(co)polymers/(co)oligomers and combinations thereof that are derivedfrom mono- and bis-phenols and mono- and bis-aldehydes selected from thegroup consisting of: phenol, alkyl- and aryl-substituted phenols;formaldehyde, and alkyl-, aryl- and heteroatom-substituted aldehydes.The phenol-aldehyde resins can be further derivatized, for example, thehydroxy group converted to an ether group. Such(co)polymers/(co)oligomers have an Mw of 20,000 or less or 10,000 orless. Other useful dielectric polymers include poly(vinyl acetate)homopolymers having an Mw of 100,000 or less.

The above polymers can be plasticized for improved flexibility,adhesion, compatibilization with an IR dye, among other characteristics.In certain instances, the plasticizer can be selected from the aboveclasses of polymers. For example, a higher Tg or higher molecular weight(Mw) phenol-aldehyde polymer can be blended with a lower Tg or lower Mwphenol-aldehyde polymer. Another example is PHS blended with aphenol-aldehyde polymer. Examples of suitable plasticizers for some ofthe above classes of polymers comprise poly(ethylene) glycol, glycerolethoxylate, di(ethylene glycol) dibenzoate, and phthalate-basedplasticizers such as dibutyl phthalate. A number of potentially suitableplasticizers for various polymers and details regarding their use can befound in the following reference: “Handbook of Plasticizers,” Ed. G.Wypych, ChemTec Publishing, Toronto, Ontario, 2004.

Source and Drain Electrodes

The source electrode and drain electrode are separated from the gateelectrode by the gate dielectric while the organic semiconductor layerderived from the layer of aromatic, non-polymeric amic acid salt can beover or under the source electrode and drain electrode. The source anddrain electrodes can be any useful electrically conductive materialincluding but not limited to, those materials described above for thegate electrode, for example, aluminum, barium, calcium, chromium, gold,silver, nickel, palladium, platinum, titanium, polyaniline, PEDOT:PSS,other conducting polymers, alloys thereof, combinations thereof, andmultilayers thereof.

The thin film electrodes (for example, gate electrode, source electrode,and drain electrode) can be provided by any useful means such asphysical vapor deposition (for example, thermal evaporation, sputtering)or ink jet printing. The patterning of these electrodes can beaccomplished by known methods such as shadow masking, additivephotolithography, subtractive photolithography, printing, microcontactprinting, and pattern coating.

The organic semiconducting layer can be located over or under the sourceand drain electrodes, as described above in reference to the thin filmtransistor articles. Useful articles can also include an integratedcircuit comprising a plurality of OFET's made by the process describedherein. The n-channel organic semiconductor layer derived from theabove-described aromatic, non-polymeric amic acid salt is capable ofbeing formed on any suitable substrate that can comprise the support andany intermediate layers such as a dielectric or insulator material,including those known in the art.

Processing

Organic semiconductor layers can be readily prepared by solution coatingof an aromatic, non-polymeric amic acid salt and after the coatingsolvent is removed, thermal dehydration imidization conversion of thearomatic, non-polymeric amic acid salt in the coating to thecorresponding arylene diimide compound in solid thin film form. Theresulting organic semiconductor layer or the layer(s) of the gatedielectric can be deposited by spin coating. The entire process ofmaking the thin film transistor devices or integrated circuits can becarried out below a maximum support temperature generally at or below450° C. or typically at or below 250° C., or even at or below 200° C.The temperature selection generally depends on the nature of thearomatic, non-polymeric amic acid salt, support, and processingparameters known in the art, once a skilled artisan has the knowledge ofthe teaching contained herein. These temperatures are well belowtraditional integrated circuit and semiconductor processing temperaturesthat enable the use of any of a variety of relatively inexpensivesupports, such as flexible polymeric supports. Furthermore, since thearomatic, non-polymeric amic acid salts are soluble in a number ofsolvents it affords flexibility in coating formulations and conditions.This enables production of relatively inexpensive integrated circuitscontaining organic thin film transistors using a significantlysimplified process.

In cases where the gate dielectric is a polymer, both the organicsemiconductor layer and the gate dielectric layer can be deposited fromsolution, making the coating of large areas less difficult. Furthermore,the aromatic, non-polymeric amic acid salts are soluble in a number ofsolvents, providing coating and manufacturing flexibility.

In one embodiment, an FET structure of FIG. 1 a is prepared by spincoating the aromatic, non-polymeric amic acid salt layer onto thedielectric layer with pre-patterned source and drain electrodes. Inanother embodiment, an FET structure of FIG. 1 c is prepared by spincoating the aromatic, non-polymeric amic acid salt onto the substratewith pre-patterned source and drain electrodes. Heating the layer atappropriate temperature and time converts the aromatic, non-polymericamic acid salt to obtain the corresponding semiconductive arylenediimide compound. Next, a dielectric layer in the form of a polymer isspin coated onto the organic semiconductor layer followed by thedeposition of the gate electrode by vacuum deposition or liquiddeposition of a conductive metal or metal dispersion, respectively.Thermal conversion of the aromatic, non-polymeric amic acid salt to thearylene diimide compound can be accomplished as described above.

Devices of this invention in which the n-channel organic semiconductorlayers can be formed include thin film transistors (TFT's), especiallyOFET's. Such layers can be used also in various types of devices havingorganic p-n junctions, such as the devices described on pages 13-15 ofU.S. Patent Application Publication 2004/0021204 (Liu).

Electronic devices of this invention in which FET's and other devicesare useful include, for example, more complex circuits such as shiftregisters, integrated circuits, logic circuits, smart cards, memorydevices, radio-frequency identification tags, backplanes for activematrix displays, active-matrix displays (for example liquid crystal orOLED), solar cells comprising a multiplicity of thin-film transistors,ring oscillators, and complementary circuits, such as inverter circuits,for example, in combination with other transistors made using availablep-type organic semiconductor materials such as pentacene. In an activematrix display, a thin film transistor device can be used as part ofvoltage hold circuitry of a pixel of the display. In devices containingFET's, the FET's are operatively connected in ways that are known in theart. In some embodiments, a multiplicity of thin-film transistors aredeposed on a non-participating support that is optionally flexible.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. An article comprising a substrate having disposed thereon a dry layerthat comprises an aromatic, non-polymeric amic acid salt.

2. The article of embodiment 1 wherein the dry layer consistsessentially of the aromatic, non-polymeric amic acid salt.

3. The article of embodiment 1 wherein the dry layer consistsessentially of the aromatic, non-polymeric amic acid salt and an aminecatalyst.

4. The article of embodiment 1 wherein the dry layer consists of thearomatic, non-polymeric amic acid salt.

5. The article of any of embodiments 1 to 4 wherein the aromatic,non-polymeric amic acid salt is thermally convertible to asemiconductive arylene diimide.

6. The article of any of embodiments 1 to 5 wherein the dry layer is acontinuous layer.

7. The article of any of embodiments 1 to 5 wherein the dry layer is apatterned layer.

8. The article of any of embodiments 1 and 4 to 7 wherein the dry layerfurther comprises an amine catalyst for the thermal conversion of thearomatic, non-polymeric amic acid salt to a corresponding arylenediimide.

9. The article of any of embodiments 1 to 8 comprising a gate dielectriclayer, a gate electrode, a source electrode, the dry layer containingthe aromatic, non-polymeric amic acid salt, and a drain electrode,

wherein the dielectric layer, the gate electrode, the dry layercontaining the aromatic, non-polymeric amic acid salt, source electrode,and the drain electrode are in any sequence as long as the gateelectrode and thin organic semiconductor film both contact thedielectric layer, and the source electrode and the drain electrode bothcontact the dry layer of the aromatic, non-polymeric amic acid salt, and

wherein the dry layer of the aromatic, non-polymeric amic acid salt iscontinuous.

10. The article of embodiment 9 comprising:

a plurality of the electrically conducting gate electrodes disposed onthe substrate,

the gate dielectric layer disposed on the electrically conducting gateelectrodes,

the dry layer containing the aromatic, non-polymeric amic acid saltdisposed on the dielectric layer substantially overlapping the gateelectrodes, and

a plurality of sets of the source electrodes and drain electrodesdisposed on the dry layer containing the aromatic, non-polymeric amicacid salt such that each of the sets is in alignment with each of thegate electrodes.

11. The article of any of embodiments 1 to 10 wherein the aromatic,non-polymeric amic acid salt is represented by either Structure (I) or(II):

wherein: Ar is an anthracene, naphthalene, or perylene nucleus and thefour carbonyl groups are attached directly to peri carbon atoms, thenon-cation A₁, A₂, and A₃ groups are independently aryl, heteroaryl,non-aromatic alkyl, alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclylgroups, and the four A₁ groups in the cations represent the same ordifferent hydrogen atom or aryl, heteroaryl, non-aromatic alkyl,alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclyl groups, provided atleast one of the A₁ cation groups is a hydrogen atom.

12. The article of any of embodiments 1 to 10 wherein the aromatic,non-polymeric amic acid salt is represented by either Structure (Ia) or(IIa):

wherein: Ar is an anthracene, naphthalene, or perylene nucleus and thefour carbonyl groups are attached directly to peri carbon atoms, thenon-cation A₁, A₂, and A₃ groups are independently aryl, heteroaryl,non-aromatic alkyl, alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclylgroups, and the three A₁ groups in the cations represent the same ordifferent hydrogen atom or aryl, heteroaryl, non-aromatic alkyl,alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclyl groups, provided atleast one of the A₁ cation groups is a hydrogen atom.

13. The article of any of embodiments 1 to 10 wherein the aromatic,non-polymeric amic acid salt is represented by either Structure (Ib) or(IIb):

wherein: Ar is an anthracene, naphthalene, or perylene nucleus and thefour carbonyl groups are attached directly to peri carbon atoms, thenon-cation A₁, A₂, and A₃ groups are independently aryl, heteroaryl,non-aromatic alkyl, alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclylgroups, and the A₁ group in the cations represent a hydrogen atom or anaryl, heteroaryl, non-aromatic alkyl, alkylaryl, fluoroalkyl,cycloalkyl, or heterocyclyl groups.

14. The article of any of embodiments 1 to 13 wherein the aromatic,non-polymeric amic acid salt is present in the dry layer in an amount ofat least 98 and up to 100 weight % based on total dry layer weight.

15. The article of embodiments 9 or 10 wherein the source, drain, andgate electrodes each independently comprise a material selected fromdoped silicon, metal, and a conducting polymer.

16. The article of any of embodiments 1 to 15 wherein the substrate isflexible.

17. The article of any of embodiments 1 to 16 comprising a flexibleremovable polymeric support that is adhered to a rigid substrate.

18. The article of any of embodiments 1 to 17 wherein the aromatic,non-polymeric amic acid salt is one or more of the Compounds I-1 throughI-58 as described above.

The present invention is demonstrated by the following examples that areintended to be exemplary and not limiting in any manner.

INVENTION EXAMPLE 1 Preparation ofdi-(cyclopentylammonium)-4,8-bis(cyclopentylcarbamoyl)-naphthalene-1,5-dicarboxylateas a Mixture of trans- and cis-isomers (Compounds I-26 and I-29)

To a stirred dispersion of 1,4,5,8-naphthalene tetracarboxylic aciddianhydride (46 mg) in tetrahydrofuran (4 ml), a solution ofcyclopentylamine (mg) in tetrahydrofuran (1 ml) was added dropwise toobtain first a clear pale yellow solution that quickly turned cloudy.Stirring was continued for an additional 5 minutes then excess diethylether was added to obtain a precipitate that was filtered, washed withdiethyl ether, and dried in air.

¹H and ¹³C NMR spectra of the product were consistent with the saltbeing a mixture of cis and trans isomers. The aromatic protons of thetrans-isomer appeared as a two doublets at 7.79 ppm (J=7.60 Hz) and 7.63ppm (J˜7 Hz); aromatic protons of the cis isomer appeared as singlets at7.81 ppm and 7.62 ppm. From the integrated areas of the aromaticprotons, it was determined that the product was a 1:1 mixture of cis andtrans amic acid salt. ¹H NMR (CD₃OD, 300 MHz) δ(ppm)=7.81 ppm (s, 2H,cis isomer), 7.79 (2H, J=7.60 Hz, trans isomer), 7.63 (s, 2H, J=7 Hz,trans isomer), 7.62 (s, 2H, cis isomer), 4.28 (m, 2H), 3.48 (m, 2H), 2(m, 8H), 1.63 (m, 26H). ¹³C NMR (CD₃OD) δ(ppm)=174.99, 170.98, 139.81,137.82, 136.54, 128.48, 127.11, 126.82, 126.26, 126.06, 51.97, 32.30,30.88, 23.74, 23.69.

INVENTION EXAMPLE 2 Conversion ofdi-(cyclopentylammonium)-4,8-bis(cyclopentylcarbamoyl)-naphthalene-1,5-dicarboxylateas a Mixture of trans and cis isomers (Compounds I-26 and I-29) toN,N′-bis-cyclopentyl Naphthalene Diimide in Solid State

A solution ofdi-(cyclopentylammonium)-4,8-bis(cyclopentylcarbamoyl)-naphthalene-1,5-dicarboxylatesalt in methanol (2 weight %) was spin coated on a glass plate andsolvent evaporated at 40-50° C. The thin solid film of the salt was thenheated at 180° C. for 10 minutes and resulting product dissolved inCDCl₃ and ¹H NMR spectrum recorded and compared with an authentic sampleof N,N′-bis(cyclopentyl)naphthalene diimide. The 1H NMR spectrum of theproduct obtained by solid state thermal conversion of amic acid salt wasidentical to that of the authentic sample. This clearly demonstratedthat the amic acid salt can be easily converted to the correspondingdiimide in thin solid film. ¹H NMR (CDCl₃, 300 MHz) δ(ppm)=8.72 (s, 4H),5.55 (q, 2H, J=8.2 Hz), 2.35-1.37 (m, 16H). IR spectra before and afterheating clearly showed the formation of diimide in thin solid film (seeFIGS. 2 a and 2 b). Furthermore the X-ray diffraction pattern of theN,N′-bis(cyclopentyl)naphthalene diimide prepared by solid state thermalconversion of precursor salt was identical to the powder X-raydiffraction pattern of the authentic sample (FIG. 3), confirming thehigh purity of diimide obtained by the inventive method.

OTFT Test Device Preparation Employing an Arylene Diimide Generated froman Amic Acid Salt:

Dielectric Preparation:

A heavily doped Si wafer with thermally grown SiO₂ (200 nm) dielectriclayer was used as substrate. The SiO₂ surface was modified byspin-coating a 5 weight % solution of Cyclotene 3022-35 resin (DowChemical) in mesitylene at 3000-5000 rpm. The Cyclotene resin-coatedSi/SiO₂ wafer was placed on a hot plate and gradually heated from 50° C.to 150° C. under an inert atmosphere over a period of 15 minutes.Finally, the temperature was increased to 250° C. and was held for 30minutes. Each sample was gradually cooled to room temperature over aperiod of 30 minutes. The thickness of each coated Cyclotene resin layercoated was in the range of 15 to 20 nm.

Coating of Salt Precursor and Thermal Conversion to Diimide:

A 0.5 weight % solution ofdi-(cyclopentylammonium)-4,8-bis(cyclopentylcarbamoyl)-naphthalene-1,5-dicarboxylate(as a mixture of trans- and cis-isomers of Compounds I-26 and I-29) inethanol-CHCl₃ (1:1) containing triethylamine (2 weight %) was spincoated on Cyclotene-resin modified SiO₂ surface. Sample was heated on ahotplate initially at 50° C. to remove the solvent and then temperaturewas raised to 180° C. over a period of about 5 minutes and the wafer washeated at 180° C. for 10 minutes in air. The resulting thin film ofN,N′-bis(cyclopentyl)naphthalene diimide was used as a n-typesemiconductor. The thickness of the semiconductor layer was a variablein some experiments, but was estimated to be 17-25 nm. OTFT devicesusing top source-drain contact configuration were made by depositinggold source drain contacts of thickness 60 nm through a shadow mask. Thechannel width was held at 650 μm while the channel lengths were variedbetween 50 and 150 μm.

Device Measurement and Analysis:

Electrical characterization of the devices prepared above was performedusing a Hewlett Packard HP 4145B® semiconductor parameter analyzer. Theprobe measurement station was held in a positive argon environment forall measurements with the exception of those purposely used for testingthe stability of the devices in air. For each experiment performed,between 4 and 12 individual devices were tested on each sample prepared,and the results were averaged. For each device, the drain current(I_(d)) was measured as a function of source-drain voltage (V_(d)) forvarious values of gate voltage (V_(g)). For most devices, V_(d) wasswept from 0 V to 100 V for each of the gate voltages measured,typically 0 V, 25 V, 75 V, and 100 V. In these measurements, the gatecurrent (I_(g)) was also recorded in order to detect any leakage currentthrough the device. Furthermore, for each device the drain current wasmeasured as a function of gate voltage for various values ofsource-drain voltage. For most of the devices, Vg was swept from 0 V to100 V for each of the drain voltages measured, typically 25 V, 75 V, and100 V.

The log of the drain current as a function of gate voltage was plotted.Parameters extracted from the log I_(d) plot included the I_(on)/I_(off)ratio and the sub-threshold slope (S). The I_(on)/I_(off) ratio issimply the ratio of the maximum to minimum drain current, and S is theinverse of the slope of the I_(d) curve in the region over which thedrain current is increasing (that is, when the device is turning on).

The thin film transistor devices were evaluated in an argon atmosphereusing a Hewlett-Packard 4145B® semiconductor parameter analyzer. Foreach thin film transistor device, the field effect mobility (μ) wascalculated from the slope of the (I_(d))^(1/2) versus V_(g) plot (FIG. 4a). This plot shows the square root of I_(d) vs. V_(g) and a mobility of2×10⁻⁵ cm²/V.sec was calculated from this plot. The threshold voltageV_(T)=71 V and current modulation, as can be seen from FIG. 4 a, betweenthe on and the off state of the device was about 10³.

Device Comparison with Authentic Sample:

For comparison, a similar device was prepared using an authentic sampleof the diimide. Accordingly, a 2 weight % solution ofN,N′-bis(cyclopentyl)naphthalene diimide in chloroform was spin coatedonto Cyclotene resin-modified SiO₂ dielectric. Solvent was evaporated ona hot plate and top source-drain silver contacts of thickness 60 nmdeposited through a shadow mask. The channel width was held at 650 μmwhile the channel lengths were varied between 50 and 150 μm. The fieldeffect mobility (μ) calculated from the slope of the (I_(d))^(1/2)versus V_(g) plot (FIG. 4 b) was of 1×10⁻⁴ cm²/V.sec was calculated fromthis plot. The threshold voltage V_(T)=67 V and current modulation, ascan be seen from FIG. 4 b, between the on and the off state of thedevice was about 10⁴.

This example clearly demonstrates that the semiconductive performance ofarylene diimide obtained via thin solid film thermal conversion of anaromatic, non-polymeric amic acid salt performed comparable to anauthentic diimide.

INVENTION EXAMPLE 3 Preparation ofdi-(cyclohexylammonium)-4,8-bis(cyclohexylcarbamoyl)-naphthalene-1,5-dicarboxylateas a Mixture of trans and cis isomers

To a stirred dispersion of 1,4,5,8-naphthalene tetracarboxylic aciddianhydride (46 mg, 0.17 mmol) in tetrahydrofuran (4 ml), a solution ofcyclohexylamine (68 mg, 0.68 mmol) in tetrahydrofuran (1 ml) was addeddropwise to obtain first a clear pale yellow solution that quicklyturned cloudy. Stirring was continued for an additional 5 minutes, thenexcess diethyl ether was added to obtain a precipitate that wasfiltered, washed with diethyl ether, and dried in air.

¹H and ¹³C NMR spectra of the product were consistent with the saltbeing a mixture of cis and trans isomers. The aromatic protons of thetrans-isomer appeared as a two doublets at 7.78 ppm (J=7.60 Hz) and 7.63ppm (J˜7 Hz); aromatic protons of the cis isomer appeared as singlets at7.81 ppm and 7.61 ppm. From the integrated areas of the aromaticprotons, it was determined that the product was a 1:1 mixture of cis andtrans amic acid salt. ¹H NMR (CD₃OD, 300 MHz) δ(ppm)=7.81 ppm (s, 2H,cis isomer), 7.78 (2H, J=7.60 Hz, trans isomer), 7.63 (s, 2H, J=7 Hz,trans isomer), 7.61 (s, 2H, cis isomer), 3.90-3.78 (m, 2H), 3.0-2.86 (m,2H), 2.09-2.16 (m, 4H), 1.98-1.60 (m, 18H), 1.5-1.1 (m, 20H). ¹³C NMR(CD₃OD) δ(ppm)=175.23, 170.46, 141.38, 140.01, 137.94, 136.63, 128.46,128.43, 127.09, 126.78, 126.23, 125.97, 51.15, 49.29, 49.25, 32.47,31.04, 25.70, 25.20, 24.81.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

Parts List: 10 substrate 20 gate dielectric 30 semiconductor 40 sourceelectrode 50 drain electrode 60 gate electrode

The invention claimed is:
 1. An article comprising a substrate havingdisposed thereon a dry layer that comprises an aromatic, non-polymericauric acid salt that is thermally convertible to a semiconductivearylene diimide.
 2. The article of claim 1 wherein the dry layerconsists essentially of the aromatic, non-polymeric amic acid salt. 3.The article of claim 1 wherein the dry layer consists essentially of thearomatic, non-polymeric amic acid salt and an amine catalyst.
 4. Thearticle of claim 1 wherein the dry layer consists of the aromatic,non-polymeric amic acid salt.
 5. The article of claim 1 wherein the drylayer is a patterned layer.
 6. The article of claim 1 wherein the drylayer further comprises an amine catalyst for the thermal conversion ofthe aromatic, non-polymeric amic acid salt to a corresponding arylenediimide.
 7. The article of claim 1 comprising a gate dielectric layer, agate electrode, a source electrode, the dry layer containing thearomatic, non-polymeric amic acid salt, and a drain electrode, whereinthe dielectric layer, the gate electrode, the dry layer containing thearomatic, non-polymeric amic acid salt, source electrode, and the drainelectrode are in any sequence as long as the gate electrode and thinorganic semiconductor film both contact the dielectric layer, and thesource electrode and the drain electrode both contact the dry layer ofthe aromatic, non-polymeric amic acid salt, and wherein the dry layer ofthe aromatic, non-polymeric amic acid salt is continuous.
 8. The articleof claim 7 comprising: a plurality of the electrically conducting gateelectrodes disposed on the substrate, the gate dielectric layer disposedon the electrically conducting gate electrodes, the dry layer containingthe aromatic, non-polymeric amic acid salt disposed on the dielectriclayer substantially overlapping the gate electrodes, and a plurality ofsets of the source electrodes and drain electrodes disposed on the drylayer containing the aromatic, non-polymeric amic acid salt such thateach of the sets is in alignment with each of the gate electrodes. 9.The article of claim 7 wherein the aromatic, non-polymeric amic acidsalt is represented by either Structure (I) or (II):

wherein: Ar is an anthracene, naphthalene, or perylene nucleus and thefour carbonyl groups are attached directly to peri carbon atoms, thenon-cation A₁, A₂, and A₃ groups are independently aryl, heteroaryl,non-aromatic alkyl, alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclylgroups, and the four A_(l) groups in the cations represent the same ordifferent hydrogen atom or aryl, heteroaryl, non-aromatic alkyl,alkylaryl, fluoroalkyl, cycloalkyl, or heterocyclyl groups, provided atleast one of the A_(l) cation groups is a hydrogen atom.
 10. The articleof claim 7 wherein the source, drain, and gate electrodes eachindependently comprise a material selected from doped silicon, metal,and a conducting polymer.
 11. The article of claim 1 wherein thearomatic, non-polymeric auric acid salt is present in the dry layer inan amount of at least 98 and up to 100 weight % based on total dry layerweight.
 12. The article of claim 1 wherein the substrate is flexible.13. The article of claim 1 comprising a flexible removable polymericsupport that is adhered to a rigid substrate.
 14. An article comprisinga substrate having disposed thereon a dry layer that comprises anaromatic, non-polymeri amic acid salt, wherein the aromatic,non-polymeric amic acid salt is one or more of the following CompoundsI-1 through I-58: